Holosun 515cu--good little sight - Holosun Paralow HS515CU Micro Red Dot Sight with Solar Power

Got mine mounted to my AR. Quick release lever has a little button that locks it in place, so the lever stays down and the sight stays locked on tight. Sight picture (2 moa dot with circle) is clear and the brightness is adjustable manually or automatically, your choice. With the high mounts provided, you can co-witness easily and clearly. Oh, by the way, the flip-caps CAN be rotated to open any direction you like; you just have to unscrew them a little, then tighten them back when you have them positioned the way you want.
The only downside to this sight is the battery compartment. It comes with a slide-out removable battery tray that accepts a CR2032 lithium battery (included). To access the tray for battery insertion, you have to remove two tiny, tiny little screws. Using the accompanying screwdriver tool on such small screws is a pain and will have you cussing in no time. My recommendation is to use the screwdriver that comes in an eyeglass repair kit--MUCH easier! Once the screws are out, the tray has to be pried out using the other end of the little tool. The battery has to be placed on the tray with the NEGATIVE SIDE UP, contrary to what you may have experienced before. Even with the battery inserted properly, the tray goes in so tightly, I was afraid I'd done something wrong and was forcing it to the point of rendering it inoperable. This was not the case, however, and the sight works like a champ.
Overall, 5 of 5 for the way it works so long as I don't have to change the battery in a hurry or in the dark.